In the game of golf, a golf club is used to hit a golf ball along a fairway often several hundred yards long, with the ultimate goal of putting the golf ball into a cup just a few inches wide. Simply stated, the object of the game is to put the ball into the cup with as few hits as possible, and it requires great skill and accuracy to meet this goal consistently. While both skill and accuracy are a function of the physical and mental abilities of the golfer, a golfer's equipment has been found to play an important role as well.
For example, some golfers may find they consistently "slice" shots hit with one club (the ball veers to one side of the intended direction), "hook" shots hit with another club (the ball veers to the other side of the intended direction), and hit accurately with yet a third club. Slicing or hooking a shot generally means that the shot will not be as accurate as one without slicing or looking. Similar variations may be found in the distance the ball travels when hit by a particular golfer. Since the accuracy and distance of shots are key factors in winning at golf, a broad range of types and styles of golf clubs have been developed.
A golf club is made up of a shaft by which the club is held by a player and swung, and a head at one end of the shaft for striking a golf ball when the club is swung. The head is attached to the shaft by a shaft-receiving socket formed in the head. This socket is known as the hosel of the head. Conventionally, the hosel fits tightly over the shaft, and the head is bonded to the shaft by epoxy.
Clubs are grouped broadly as woods and irons, with woods having a type of head designed for long distance hits (or drives), and irons having heads designed for shorter hits, or special-situation hits like hitting a ball out of tall grass or a sand trap, or putting the ball when on the green. Particular clubs may be distinguished from others generally by the length and weight of the shaft, the size and weight of the head, and the geometric configuration of the head that determine various angles and displacements of the shaft relative to the ball-striking face of the head. Typically, a club designed for hitting a ball a long distance has a longer shaft and a bigger head than a club designed for hitting the ball a shorter distance.
Since golfers come in all sizes, golf clubs come in various sizes. However, two golfers of the same height and arm length may prefer to play with clubs having different shaft lengths for a given head design, or having different head-to-shaft angles and displacements for a given shaft design. Thus, for optimum performance of a club, the shaft length must be matched to both the geometric configuration of the head and the player holding the shaft. Given the tight fitting hosels of conventional heads, this usually requires a compromise, with the head being chosen to approximate the desired angles and displacements, and the shaft length being matched just to the player, regardless of how this length may change the optimum ball-striking position of the head. All of this is complicated further by the fact that some golfers play with right-handed clubs having the hosel located on the left side of the head, while others play with left-handed clubs having the hosel on the right side of the head.
One way to avoid the compromise discussed above would be to manufacture a whole series of heads of a particular model line, providing a family of heads having a range of angles and displacements from which to choose. This can often be quite expensive for the head manufacturer, multiplying the number of molds required to make a line of heads, and complicating manufacturing and processing. It also requires that the manufacturer gauge market demand within each line of heads for each particular combination of angles and displacements.
For very demanding golfers, and particularly professional golfers, different angles and displacements may be identified for each type of club, and may be identified with such accuracy that the desired angles and displacements are not available from existing molds. Accordingly, the needs of many golfers simply are not met, or are met only at the expense of custom casting of the heads. Furthermore, the delay associated with custom casting may force many players to resort to heads that are readily available, to the detriment of their game.
There is thus a great need for some combination of golf club head and shaft that can be used to meet the exact needs of each golfer economically, accurately, and quickly. The embodiments disclosed herein do just that by providing a head with a hosel that is oversized relative to the shaft, and by attaching the head to the shaft at the desired angles and displacements through the use of a hosel-insert interposed the shaft and the hosel. The interior of the invented hosel preferably is rectangularly shaped. Furthermore, the sole plate of the head is slightly curved to provide better ground contact between the sole plate and the ground, for any particular angular displacement of the head relative to the shaft. The combination of the shaft, hosel and sole plate have been found to provide a superior combination of customizability and playability for the resulting golf clubs.
U.S. Pat. Nos. 3,625,513 and 3,907,446 show golf clubs with heads attached to shafts by hosels that provide minimal adjustability of shaft-to-head angles. However, in both of these patents the hosel is shown to be relatively close-fitting with the shaft, and cylindrical to match the cylindrical shape of the shaft. This allows only the most minimal adjustments of angles, and leaves no room for adjusting the displacements of the head relative to the shaft, as discussed in more detail below.
It is common for a wood to be swung with a head velocity of over 100 mph. Accordingly, conventional wisdom has required a tight-fitting hosel to prevent bending, breaking, or creating excessive shock or vibration. Thus, a typical golf club has a steel shaft with a tight-fitting hosel at one end and further includes a shock-absorbing grip at the other end of the shaft. Even with the heads in U.S. Pat. Nos. 3,625,513 and 3,907,446, this wisdom dictated close-fitting hosels very similar to the tight-fitting hosels of conventional design.
U.S. Pat. No. 5,513,844, incorporated herein by reference, discusses club fitting in the context of what is described as a club-fitting apparatus. However, the apparatus requires the use of a number of different club heads, each having a hosel at different angles, with the hosel releasably clamping a shaft in a close-fitting relationship. Furthermore, the apparatus does not appear to be intended for more normal golf use. Rather, it is described only with respect to testing clubs, not playing with them. Accordingly, the apparatus of U.S. Pat. No. 5,513,844 does not provide a desirable solution to the problems addressed by the present invention.
The present invention, in various embodiments described in more detail below, shows that the conventional hosel design is subject to great improvement. This results in greatly improved golf clubs that are easier to manufacture. The improvements are noticeable when a head including one of the various hosels described herein is used on a conventional shaft, and even more noticeable when such a head is combined with an appropriately selected shaft.
The advantages of the present invention will be understood more readily after a consideration of the drawings and the following detailed description.